bugfix dropdown-menu in footer

WIP #2

basetheme_bootstrap/static/css/basetheme_bootstrap4_pasteur.css

@@ -103,6 +103,7 @@ header .dropdown.show>a {
     background: #211b1d;
 }
 
+footer .dropdown-menu ,
 header .dropdown-menu {
     background: #211b1d;
     border-color:#fff;